commit fb8899a597c5ef39706215a894fc8c5f5dbf85bc
author Raymond Hettinger <python@rcn.com> Mon May 26 00:40:09 2014 -0700
committer Raymond Hettinger <python@rcn.com> Mon May 26 00:40:09 2014 -0700
tree 01ef4ab677dc3fb8edb3a2c36202f21ca27ff0a7
parent f643b9a9c79928c4ca28d895e7e9a1dcf827cf00

Issue #21481:  Teach argparse equality tests to return NotImplemented when comparing to unknown types.

Lib/test/test_argparse.py

diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index fdf2b67..0df66ad 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4453,6 +4453,12 @@
         self.assertTrue(ns2 != ns3)
         self.assertTrue(ns2 != ns4)
 
+    def test_equality_returns_notimplemeted(self):
+        # See issue 21481
+        ns = argparse.Namespace(a=1, b=2)
+        self.assertIs(ns.__eq__(None), NotImplemented)
+        self.assertIs(ns.__ne__(None), NotImplemented)
+
 
 # ===================
 # File encoding tests